Recently, motorcycles equipped with an airbag module have been developed. Upon detection of a collision, the airbag module inflates and deploys an airbag to mitigate the impact that the rider receives. A motorcycle that is equipped with an airbag module is disclosed in, for example, Japanese Patent Application Laid-open Publication No. 2005-153613. FIG. 7 is a front view (a view seen from the rider's side) of an air bag that is inflated and deployed in front of the rider, in a conventional airbag module. The shape of the front face (the shape seen from the rider's side) of the conventional airbag is designed to have an inverted triangular shape with the upper part overall wider than the lower part. In addition, a recess 101 extending in a longitudinal direction is formed in the front face of an airbag 100. Hence, the front face of the airbag 100 forms a cross section having a v-shape, the center of which is recessed while the right and left sides protrude. Accordingly, when the rider of the motorcycle is pressed against the deployed airbag 100, this v-shape effectively prevents lateral movement of the rider, thereby making it easier to catch the rider at a center part of the front face of the airbag 100. Note that, one end portion of each of two straps 102 and 103 for keeping the airbag 100 in a predetermined shape is joined to the center of the front face of the airbag 100. The other end portions of the respective straps 102 and 103 are joined to the frame body of the motorcycle.